Circular dichroism in the angular distribution of valence photoelectrons emitted from randomly oriented 3-hydroxytetrahydrofuran enantiomers (Th(S) and Th(R)) has been observed in gas-phase experiments using circularly polarized vacuum ultraviolet (VUV) light. The measured dichroism for both Th(S) and Th(R), acquired at the single magic angle theta=234.73 degrees and at photon energies of 22, 19, 16, and 14 eV, points to an asymmetric forward-backward scattering of the photoelectrons from their highest occupied molecular orbitals (HOMO) HOMO-1 and HOMO-2, of up to 5%, depending on the photon energy. The asymmetry reverses on exchange of either the helicity of the radiation or the configuration of Th. The photoionization dichroic D parameters of Th(S) and Th(R) have been measured and their values discussed in the light of LCAO B-spline density functional theory (DFT) predictions. While an acceptable agreement is found between the dichroic parameter measured and calculated at the highest photon energy for the HOMO and HOMO-2 orbitals of Th, a significant discrepancy is observed for the HOMO-1 state which is attributed to the floppiness of Th, in particular to the comparatively large sensitivity of the size and shape of its HOMO-1 on nuclear vibrational motion.
Angle-resolved photoelectron spectroscopy of randomly oriented 3-hydroxytetrahydrofuran enantiomers / Giardini, Anna; Daniele, Catone; Stranges, Stefano; Mauro, Satta; Tacconi, Mario; Susanna, Piccirillo; Stefano, Turchini; Nicola, Zema; Giorgio, Contini; Tommaso, Prosperi; Pietro, Decleva; Devis Di, Tommaso; Giovanna, Fronzoni; Mauro, Stener; Filippi, Antonello; Speranza, Maurizio. - In: CHEMPHYSCHEM. - ISSN 1439-4235. - STAMPA. - 6:6(2005), pp. 1164-1168. [10.1002/cphc.200400483]